How severe is CVE-2025-6543?

No CVSS score has been assigned to CVE-2025-6543 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-6543?

Affected package information for CVE-2025-6543 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2025-6543?

No fixed release is recorded for CVE-2025-6543 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2025-6543 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2025-6543 if there is no patch (or I can't update yet)?

Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Is CVE-2025-6543 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2025-6543, including . All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2025-6543?

CVE-2025-6543 has an EPSS (Exploit Prediction Scoring System) score of 10.6%, placing it in the 96th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

Is CVE-2025-6543 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-6543 (Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2025-06-30. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-07-21. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-6543?

CVE-2025-6543 is classified as Buffer Overflow (CWE-119). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-6543 published, and has it been updated?

CVE-2025-6543 was published on June 25, 2025 and was last updated on February 26, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV · ACTIVELY EXPLOITED

CVE-2025-6543

CVE-2025-6543 is a Buffer Overflow vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-06-30) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy,…

Published

Jun 25, 2025

Updated

Feb 26, 2026

Affected

2 products

Patched

See advisory

Exploits

2 known

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2025-06-30. Federal agencies were required to remediate by 2025-07-21.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2025-6543.

EPSS Exploitation Probability

via FIRST.org ↗

10.6%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

Affected Products

2 products · 6 configurations

Application

netscaler application delivery controllercitrix

≥ 14.1 && < 14.1-47.46

range

Application

netscaler gatewaycitrix

≥ 14.1 && < 14.1-47.46

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

abrewer251/CVE-2025-6543_CitrixNetScaler_PoC

Multi-host, multi-port scanner and auditor for CVE-2025-6543-affected Ne

⭐ 6🍴 1Jul 2026

grupooruss/Citrix-cve-2025-6543

Script para determinar si Citrix es vulnerable al CVE-2025-6543

⭐ 5🍴 0Jun 2026

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2025-6543 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2025-6543 in your dependencies?

Find it across , including transitive dependencies.

Scan my dependencies How O3 SCA works